Dimming control method and apparatus and dimming system

ABSTRACT

Embodiments of the present invention disclose a dimming control method and apparatus and a dimming system. The method according to an embodiment of the invention includes: detecting a conduction angle of a dimming apparatus according to an output signal; and controlling a first shunt load according to the conduction angle to disconnect the first shunt load upon detecting a valid conduction angle of the dimming apparatus and to keep the first shunt load conducted upon detecting no valid conduction angle of the dimming apparatus, thereby lowering power consumption.

FIELD OF THE INVENTION

The present invention relates to the field of electromechanicaltechnologies and in particular to a dimming control method and apparatusand a dimming system.

BACKGROUND OF THE INVENTION

At present a lighting load can be controlled by a phase-cutting dimmeror switch, where supply current of the dimmer or the switch flowingthrough the load may result in the lighting load flickering or failingto be disconnected, which can be addressed by an additional bypass load.The bypass load of the dimmer or the switch which is a virtual load canhave the supply current flowing through the lighting load lowered toenable the dimmer or the switch to operate normally when the load isabsent or very low.

In the prior art, the bypass load operates primarily with some simpleelement, for example, the bypass load is embodied simply as a capacitoror a powerful resistor. The inventors of the invention have identifiedfrom a research on the prior art that if the bypass load is composed ofa resistor, then the lighting load may suffer from increased powerconsumption, lowered compatibility and a larger amount of generatedheat; and if the bypass load is composed of a capacitor, then thecapacitor may have an impedance characteristic of the lighting loadaltered and may result in the lighting load flickering or failing to bedisconnected and in a narrowed dimming range of a dimmable lamp.

SUMMARY OF THE INVENTION

Embodiments of the invention provide a dimming control method andapparatus and a dimming system so as to lower power consumption.

A dimming control method includes: detecting a conduction angle of adimming apparatus according to an output signal; and controlling a firstshunt load according to the conduction angle to disconnect the firstshunt load upon detecting a valid conduction angle of the dimmingapparatus and to keep the first shunt load conducted upon detecting novalid conduction angle of the dimming apparatus.

Optionally a second shunt load is connected in parallel with the firstshunt load, and the second shunt load is kept conducted.

Optionally preset current of the first shunt load is far above that ofthe second shunt load.

Optionally the first shunt load and the second shunt load are lowimpedance loads or constant current sources.

Optionally if the dimming apparatus is in a low impedance status, thenthere is a valid conduction angle of the dimming apparatus; and if thedimming apparatus is in a high impedance status, then there is no validconduction angle of the dimming apparatus.

Optionally the detecting a conduction angle of a dimming apparatusaccording to an output signal includes: conducting the first shunt load;obtaining the output signal; and detecting a valid conduction angle ofthe dimming apparatus according to the output signal.

Optionally the dimming apparatus is a dimmer or a switch.

A control apparatus includes: a first shunt load, a detector and acontroller, wherein the first shunt load is configured to operate in aconducted status for maintaining normal operation and a disconnectedstatus for lowering power consumption; the detector is configured toobtain an output signal and to detect a conduction angle of a dimmingapparatus according to the output signal; and the controller isconfigured to control the first shunt load according to the conductionangle detected by the detector so that the controller controls the firstshunt load to be disconnected when the detector detects a validconduction angle of the dimming apparatus; and the controller keeps thefirst shunt load conducted when the detector detects no valid conductionangle of the dimming apparatus.

Optionally the control apparatus further includes a second shunt load,wherein the second shunt load is connected in parallel with the firstshunt load, and the second shunt load is kept conducted; and presetcurrent of the first shunt load is far above that of the second shuntload.

Optionally the first shunt load and the second shunt load are lowimpedance loads or constant current sources.

Optionally the dimming apparatus is a dimmer or a switch.

A dimming system includes a dimming apparatus and any control apparatusdescribed above, wherein the dimming apparatus is configured to performdimming and to output a conduction angle; and the control apparatus isconfigured to detect a conduction angle of the dimming apparatus tocontrol the first shunt load disconnected upon detecting a validconduction angle of the dimming apparatus and to keep the first shuntload conducted upon detecting no valid conduction angle of the dimmingapparatus.

Optionally the dimming system further includes a lighting load withwhich the control apparatus is connected.

As can be apparent from the foregoing technical solutions, theembodiments of the invention have the following advantages:

The invention detects the conduction angle of the dimming apparatusaccording to the output signal, and disconnects the first shunt loadupon detecting a valid conduction angle of the dimming apparatus andkeeps the first shunt load conducted upon detecting no valid conductionangle of the dimming apparatus. This embodiment can detect whether thereis a valid conduction angle of the dimming apparatus and can disconnectthe first shunt load when there is a valid conduction angle of thedimming apparatus to thereby lower power consumption.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to make the technical solutions in the embodiments of theinvention more apparent, the drawings to be used in the description ofthe embodiments will be described briefly, and obviously the drawings inthe following description are illustrative of only some embodiments ofthe invention, and those ordinarily skilled in the art can derive fromthese drawings other drawings without any inventive effort. In thedrawings:

FIG. 1 is a flow chart of a dimming control method in a firstembodiment;

FIG. 2 is a flow chart of a dimming control method in a secondembodiment;

FIG. 3 is a schematic diagram of a dimming system in an embodiment ofthe invention;

FIG. 4 is another schematic diagram of a dimming system in an embodimentof the invention;

FIG. 5 is a timing diagram of a dimming control method in an embodimentof the invention;

FIG. 6 is a structural diagram of a control apparatus in a thirdembodiment;

FIG. 7 is another structural diagram of a control apparatus in a thirdembodiment; and

FIG. 8 is a structural diagram of a dimming system in a fourthembodiment.

DETAILED DESCRIPTION OF THE INVENTION

The technical solutions in the embodiments of the invention will bedescribed below clearly and fully with reference to the drawings in theembodiments of the invention, and apparently the described embodimentsare only a part but not all of the embodiments of the invention. Basedupon the embodiments of the invention, all the other embodiments derivedby those ordinarily skilled in the art without any inventive effortshall come into the scope of the invention.

An embodiment of the invention provides a dimming control method so asto lower power consumption. Embodiments of the invention further providea corresponding control apparatus and a dimming system. They will bedescribed below in details respectively.

First Embodiment

An embodiment of the invention provides a dimming control method whichwill be described from the view of a control apparatus for a convenientdescription, where the control apparatus can be a load of a dimmingapparatus or can be a bypass load of a dimming apparatus, which isconnected in parallel with a lighting load in a dimming system.

A dimming control method includes: detecting a conduction angle of adimming apparatus according to an output signal; and controlling a firstshunt load according to the conduction angle to disconnect the firstshunt load upon detecting a valid conduction angle of the dimmingapparatus and to keep the first shunt load conducted upon detecting novalid conduction angle of the dimming apparatus.

Referring to FIG. 1, a particular flow thereof can be as follows:

101. A control apparatus detects a conduction angle of a dimmingapparatus according to an output signal;

The dimming apparatus can be a dimmer or a switch for controlling adimming system. For example, if the dimming system is a lighting system,then the dimming apparatus can control lighting to be switched on/off orbright/dark.

Whether there is a valid conduction angle output from the dimmingapparatus can be detected from the output signal of the dimmingapparatus.

Optionally if the dimming apparatus is in a low impedance status, thenthere is a valid conduction angle of the dimming apparatus, and if thedimming apparatus is in a high impedance status, then there is no validconduction angle of the dimming apparatus.

Optionally the conduction angle of the dimming apparatus can be detectedparticularly in the steps of: firstly conducting a first shunt load, andthen obtaining the output signal, and next detecting the conductionangle of the dimming apparatus according to the output signal.

102. The control apparatus controls a first shunt load according to theconduction angle detected in the step 101 to disconnect the first shuntload upon detecting a valid conduction angle of the dimming apparatusand to keep the first shunt load conducted upon detecting no validconduction angle of the dimming apparatus.

In order to keep normal operation of the dimming system, a second shuntload can be connected in parallel with the first shunt load, and thesecond shunt load can be kept conducted, so that the second shunt loadcan shunt when the first shunt load is disconnected to thereby keepnormal operation.

Optionally in order to ensure the conduction angle of the dimmingapparatus to be detected, preset current of the first shunt load istypically far above that of the second shunt load.

As can be apparent from the foregoing disclosure, the invention detectsthe conduction angle of the dimming apparatus according to the outputsignal and controls the first shunt load according to the conductionangle to disconnect the first shunt load upon detecting a validconduction angle of the dimming apparatus, thereby lowering powerconsumption, and to keep the first shunt load conducted upon detectingno valid conduction angle of the dimming apparatus, thereby maintainingnormal operation without increasing power consumption. This embodimentcan detect whether there is a valid conduction angle of the dimmingapparatus and can control the status of the first shunt load accordingto the status of the valid conduction angle of the dimming apparatus tothereby ensure an impedance characteristic of the load to be invariant.

Second Embodiment

For better understanding of the foregoing solution, the technicalsolution of the invention will be described below in details in aparticular embodiments, and reference can be made to FIG. 2 for aparticular flow thereof:

201. A first shunt load is conducted.

202. An output signal is obtained;

In the step 201, the first shunt load is conducted, and at this time thecircuitry of a dimming system is in a fully closed status, and a dimmingapparatus can be controlled differently to output a different signal, sothat the status of the dimming apparatus can be detected by obtainingthe output signal of the dimming apparatus. For example, the outputsignal can be obtained in a high impedance status or a low impedancestatus.

203. A conduction angle of the dimming apparatus is detected accordingto the obtained output signal.

The dimming apparatus may generate a conduction angle in the course ofcontrolling the dimming system, but the output conduction angle may bevalid conduction angle or may be an invalid conduction angle. Whetherthe dimming apparatus outputs a valid conduction angle or an invalidconduction angle can be detected from the output signal obtained in thestep 202, where if the dimming apparatus is in a low impedance status,then there is a valid conduction angle of the dimming apparatus, and ifthe dimming apparatus is in a high impedance status, then there is novalid conduction angle of the dimming apparatus.

How to detect a conduction angle of the dimming apparatus will bedescribed below in details by way of an example in which the dimmingapparatus is a dimmer, and the first shunt load and a second shunt loadare constant current sources, where the first shunt load is described asa constant current source A, and the second shunt load is described as aconstant current source B for a convenient description, and referencecan be made to FIG. 3 and FIG. 5:

Where in this embodiment, CA represents a conduction angle signal of thedimmer, and the conduction angle signal CA output from the dimmer can bedetected from an output signal OUT of the dimmer, a valid conductionangle is determined from the conduction angle signal CA, and theconstant current source A can be controlled by the control signal CS tobe switched on/off according to a detection result of the output signal.

When an output signal OUT is found, at this time the constant currentsource A is kept switched on to thereby firstly have a valid conductionangle signal of the dimmer determined A timer is triggered by a fallingedge of the valid conduction angle signal to serve as a trigger signalto switch again on the constant current source A next time. It shall benoted that if the controller finds a loss of the conduction anglesignal, that is, finds that the conduction angle is not a validconduction angle, then a counting period of time of the timer will beshortened until a valid conduction phase signal is found again, wherethe counting period of time of the timer is resumed to the originalperiod of time.

Particularly referring to FIG. 5 which is a timing diagram ofcontrolling the first shunt load to be conducted/disconnected, firstly apower source of the dimming system is switched on, and the constantcurrent source A is switched on, and at this time the control signal CSis output at a high level to thereby look for a first valid conductionangle, where a period of time from a rising edge to a falling edge ofthe output signal OUT is a valid conduction angle. It shall beappreciated that all the parameters in FIG. 5 are intended to illustratean operating principle for reference.

Then after the first valid conduction angle is determined, the controlsignal CS is maintained, and the output signal OUT is observed, and thena next timed output of the control signal is determined according toperiodicity information of utility power and the valid conduction anglesignal, where after the first valid conduction angle signal is found,the control signal continues with its output at a high level until theoutput signal OUT is output again at a high level and the constantcurrent source A is switched off.

Where in order to ensure the output signal OUT not to be output again ata high level due to noise or the like, a period of time for waiting isnecessary, for example, there is a short period of time for waiting(e.g., 70 μs) after the output signal OUT is output again at a highlevel, and at this time the control signal CS is output at a low level,and the timer is started. When the counting period of time of the timerexpires, the control signal CS will be output again at a high level,where the counting period of time of the timer can be determined as halfa cycle, that is, the control signal CS will be output again at a highlevel upon counting to half a cycle from a falling edge of a last validconduction angle.

It shall be noted that in order to ensure the stability of a detectionsignal and the accuracy of counting by the timer, the counting period oftime of the timer can be determined as half a cycle minus a specificperiod of time (e.g., 0.1 ms), where it can also be detected from thecontrol signal CS when the output signal OUT is changed to a low level,and a period of time from a rising edge of last output signal OUT tothis falling edge is a valid conduction angle. This can be repeated todetect a conduction angle signal periodically.

Where if the control signal CS is output at a high level when thecounting period of time thereof expires while no output signal OUT isfound at a high level, then it indicates a loss of the currentconduction angle signal, and as illustrated in the middle of FIG. 5, thetimer will start to count again when the last counting period of timeexpires, and in order to ensure a margin of the timer, the countingperiod of time can be shortened rapidly, for example, the countingperiod of time can be shortened to half a cycle minus a specific periodof time (e.g., 0.5 ms). After the counting period of time is reset, if avalid conduction angle can be found again, then the counting period oftime of the timer will be resumed to the original value, that is, thecounting period of time is resumed to half a cycle minus a specificperiod of time (e.g., 1 ms), and if still no valid conduction angle isfound, then a next counting period of time is further shortened, forexample, the counting period of time can be shortened to half a cycleminus a specific period of time (e.g., 1 ms) until a valid conductionangle is found.

204. It is judged whether the conduction angle detected in the step 203is a valid conduction angle.

The flow proceeds to the step 205 upon detecting a valid conductionangle of the dimming apparatus; and the flow proceeds to the step 206upon detecting no valid conduction angle of the dimming apparatus.

Where this embodiment can have a second shunt load connected in parallelwith the first shunt load, and the second shunt load can be keptconducted, so that when the first shunt load is disconnected, the secondshunt load in this embodiment can shunt to thereby keep normal operationof the dimming system. Particularly referring to FIG. 3 or FIG. 4, thefirst shunt load in FIG. 3 is a constant current source A, and thesecond shunt load is a constant current source B, and the first shuntload in FIG. 4 is a low impedance load A, and the second shunt load is ahigh impedance load B.

Optionally in order to ensure accurate detection of the conduction angleof the dimming apparatus, preset current of the first shunt load istypically far above that of the second shunt load.

Where the first shunt load and the second shunt load can be lowimpedance loads or constant current sources. Referring to FIG. 3 or FIG.4, FIG. 3 is a schematic diagram of an example in which the first shuntload and the second shunt load are constant current sources, and FIG. 4is a schematic diagram of an example in which the first shunt load andthe second shunt load are low impedance loads.

205. The first shunt load is disconnected upon detecting a validconduction angle of the dimming apparatus;

Referring to FIG. 5, the first shunt load is disconnected upon detectinga valid conduction angle of the dimming apparatus, but there is a smalloverlap zone of the control signal and the conduction angle in thisembodiment, that is, the constant current source A is actually keptconducted for a short period of time, and thus there is low powerconsumption of the control apparatus, thereby lowering powerconsumption.

206. The first shunt load is kept conducted upon detecting no validconduction angle of the dimming apparatus.

The first shunt load is kept conducted upon detecting no validconduction angle of the dimming apparatus to thereby keep normaloperation without increasing power consumption, and the first shunt loadwill not be disconnected until next occurrence of a valid conductionangle.

As can be apparent from the foregoing disclosure, the invention detectsthe conduction angle of the dimming apparatus according to the outputsignal and controls the first shunt load according to the conductionangle to disconnect the first shunt load upon detecting a validconduction angle of the dimming apparatus, thereby lowering powerconsumption, and to keep the first shunt load conducted upon detectingno valid conduction angle of the dimming apparatus, thereby maintainingnormal operation without increasing power consumption. This embodimentcan detect whether there is a valid conduction angle of the dimmingapparatus and can control the status of the first shunt load accordingto the status of the valid conduction angle of the dimming apparatus tothereby ensure an impedance characteristic of the load to be invariant.

Third Embodiment

For a better implementation of the foregoing embodiments, an embodimentof the invention further provides a control apparatus. Referring to FIG.6, this embodiment can particularly include a first shunt load 301, adetector 302 and a controller 303.

The first shunt load 301 is configured to operate in a conducted statusfor maintaining normal operation and a disconnected status for loweringpower consumption.

The detector 302 is configured to obtain an output signal and to detecta conduction angle of a dimming apparatus according to the outputsignal.

The controller 303 is configured to control the first shunt load 301according to the conduction angle detected by the detector 302 so thatthe controller 303 controls the first shunt load 301 to be disconnectedwhen the detector 302 detects a valid conduction angle of the dimmingapparatus; and the controller 303 keeps the first shunt load 301conducted when the detector 302 detects no valid conduction angle of thedimming apparatus.

Where the detector 302 can be a current detection circuit or a voltagedetection circuit.

Where the dimming apparatus can be a dimmer or a switch for controllinga dimming system. For example, if the dimming system is a lightingsystem, then the dimming apparatus can control lighting to be switchedon/off or bright/dark.

It shall be noted that the control apparatus in this embodiment can usedalone as a load of the dimming apparatus or can be used as a bypass loadof the dimming apparatus, which is connected in parallel with a lightingload in the dimming system.

Additionally, referring to FIG. 7, this embodiment can further include asecond shunt load 304 connected in parallel with the first shunt load301, where the second shunt load 304 can be kept conducted, and when thefirst shunt load 301 is disconnected, the second shunt load 304 canmaintain normal operation of the dimming system.

In order to detect validly the conduction angle of the dimmingapparatus, preset current of the first shunt load 301 in this embodimentis typically far above that of the second shunt load 304.

The first shunt load 301 and the second shunt load 304 are low impedanceloads or constant current sources.

For example, when the second shunt load 304 is a constant currentsource, and the first shunt load 301 is also a constant current source,in order to ensure the characteristic of the constant current sources, arectification circuit can be set to rectify supply current of thedimming apparatus.

Where as can be apparent from the foregoing embodiment, if the dimmingapparatus is in a low impedance status, there is a valid conductionangle of the dimming apparatus, and if the dimming apparatus is in ahigh impedance status, then there is no valid conduction angle of thedimming apparatus. That is, when the dimming apparatus is in a lowimpedance status, the first shunt load 301 is disconnected so that thisembodiment can have power consumption lowered at low impedance withoutinfluencing the impedance characteristic of the dimming system.

It shall be noted that reference can be made to the foregoing embodimentfor a particular implementation, so a repeated description thereof willbe omitted here.

As can be apparent from the foregoing disclosure, in the presentinvention, the detector 302 obtains the output signal and detects theconduction angle of the dimming apparatus according to the outputsignal, the controller 303 controls the first shunt load 301 accordingto the conduction angle detected by the detector 302 so that thecontroller 303 controls the first shunt load 301 to be disconnected whenthe detector 302 detects a valid conduction angle of the dimmingapparatus, thereby lowering power consumption; and the controller 303keeps the first shunt load conducted when the detector 302 detects novalid conduction angle of the dimming apparatus, thereby maintainingnormal operation without increasing power consumption. In thisembodiment, the controller 303 can control the status of the first shuntload according to the status of the dimming apparatus to thereby ensurean impedance characteristic of the load to be invariant.

Fourth Embodiment

The invention further provides a dimming system. Referring to FIG. 8,this embodiment can particularly include a dimming apparatus 401 and acontrol apparatus 402.

Where the dimming apparatus 401 in this embodiment can perform dimmingand output a conduction angle. The dimming apparatus 401 can be a dimmeror a switch for controlling a dimming system. For example, if thedimming system is a lighting system, then the dimming apparatus 401 cancontrol lighting to be switched on/off or bright/dark.

Where the control apparatus 402 in this embodiment can particularlyinclude a first shunt load, a detector and a controller. Particularlythe first shunt load is configured to operate in a conducted status formaintaining normal operation of the dimming system and a disconnectedstatus for lowering power consumption of the dimming system; thedetector is configured to obtain an output signal and to detect aconduction angle of the dimming apparatus 401 according to the outputsignal; the controller is configured to control the first shunt loadaccording to the conduction angle detected by the detector so that thecontroller controls the first shunt load to be disconnected when thedetector detects a valid conduction angle of the dimming apparatus 401;and the controller keeps the first shunt load conducted when thedetector detects no valid conduction angle of the dimming apparatus 401.It shall be noted that reference can be made to the foregoing embodimentfor a particular implementation of the control apparatus 402, so arepeated description thereof will be omitted here.

Where the control apparatus 402 in this embodiment can used alone as aload of the dimming apparatus 401 or can be used as a bypass load of thedimming apparatus 401, which is connected in parallel with a lightingload in the dimming system.

Optionally this embodiment can further include a lighting load withwhich the control apparatus 402 is connected in parallel for use as abypass load of the dimming apparatus 401.

As can be apparent, the control apparatus 402 can control the firstshunt load according to the status of the dimming apparatus 401 tothereby lower power consumption at low impedance and ensure an impedancecharacteristic of the load to be invariant.

The dimming control method and apparatus and the dimming systemaccording to the invention have been described above in details, and theprinciple and the embodiments of the invention have been set forth inthis context by way of particular examples, but the foregoingdescription of the invention is merely intended to facilitateunderstanding of the inventive method and the essence thereof; and alsothose ordinarily skilled in the art can modify the particularembodiments and the application scope in light of the idea of theinvention. In summary the disclosure of the specification shall not beconstrued as limiting the scope of the invention.

What is claimed is:
 1. A dimming control method, comprising: conductinga first shunt load; obtaining an output signal of a dimming apparatus;detecting a conduction angle of the dimming apparatus according to theoutput signal; and controlling the first shunt load by a control signalaccording to the conduction angle to disconnect the first shunt loadupon detecting that the dimming apparatus is in a low impedance statusthat is, there is a valid conduction angle of the dimming apparatus, andto keep the first shunt load conducted upon detecting that the dimmingapparatus is in a high impedance status, that is there is no validconduction angle of the dimming apparatus, wherein there is a smalloverlap zone of the control signal and the conduction angle, thereby thefirst shunt load is kept conducted for a short period of time.
 2. Themethod according to claim 1, further comprising: connecting a secondshunt load in parallel with the first shunt load, wherein the secondshunt load is kept conducted.
 3. The method according to claim 2,wherein: a preset current of the first shunt load is far above that ofthe second shunt load.
 4. The method according to claim 2, wherein: thefirst shunt load and the second shunt load are low impedance loads orconstant current sources.
 5. The method according to claim 1, wherein:the dimming apparatus is a dimmer or a switch.
 6. A control apparatus,comprising a first shunt load, a detector and a controller, wherein: thefirst shunt load is configured to operate in a conducted status formaintaining normal operation and a disconnected status for loweringpower consumption; the detector is configured to obtain an output signalof a dimming apparatus and to detect a conduction angle of the dimmingapparatus according to the output signal; and the controller isconfigured to control the first shunt load by a control signal accordingto the conduction angle detected by the detector so that the controllercontrols the first shunt load to be disconnected when the detectordetects that the dimming apparatus is in a low impedance status, thatis, there is a valid conduction angle of the dimming apparatus; and thecontroller keeps the first shunt load conducted when the detectordetects that the dimming apparatus is in a high impedance status, thatis, there is no valid conduction angle of the dimming apparatus, whereinthere is a small overlap zone of the control signal and the conductionangle, thereby the first shunt load is kept conducted for a short periodof time.
 7. The apparatus according to claim 6, further comprising asecond shunt load, wherein: the second shunt load is connected inparallel with the first shunt load, and the second shunt load is keptconducted; and preset current of the first shunt load is far above thatof the second shunt load.
 8. The apparatus according to claim 7,wherein: the first shunt load and the second shunt load are lowimpedance loads or constant current sources.
 9. The apparatus accordingto claim 6, wherein: the dimming apparatus is a dimmer or a switch. 10.A dimming system, comprising: the dimming apparatus and the controlapparatus according to claim 6, wherein: the dimming apparatus isconfigured to perform dimming and to output a conduction angle; and thecontrol apparatus is configured to detect the conduction angle of thedimming apparatus to control the first shunt load disconnected upondetecting a valid conduction angle of the dimming apparatus and to keepthe first shunt load conducted upon detecting no valid conduction angleof the dimming apparatus.
 11. The dimming system according to claim 10,further comprising a lighting load with which the control apparatus isconnected in parallel.